Method of making a bifurcated stent with improved side branch aperture

ABSTRACT

A stent for insertion into a blood vessel is made from a sheet having a longitudinal axis and a first portion and a second portion. The first portion has a proximal end and a distal end and a first lateral side and a second lateral side with the lateral sides of the first portion substantially parallel to the longitudinal axis and disposed apart from each other a first distance. The second portion has a proximal end and a distal end and a first lateral side and a second lateral side with the lateral sides of the second portion substantially parallel to the longitudinal axis and disposed apart from each other a second distance that is less than the first distance. The proximal end of the second portion communicates with the distal end of the first portion. The first lateral side of the first portion is connected to the second lateral side of the first portion and the first lateral side of the second portion is connected to the second lateral side of the second portion to form the stent. A portion of the distal end of the first portion and a portion of the proximal end of the second portion define a side branch aperture.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a divisional application of U.S. Ser. No. 09/575,957,filed May. 23, 2000.

FIELD OF THE INVENTION

[0002] The present invention relates to stents, and more particularly tobifurcated stents and methods of making bifurcated stents for insertionwithin a branching vessel.

BACKGROUND OF THE INVENTION

[0003] Stents are well known in the art. They are typically formed of acylindrical metal mesh which can expand when pressure is internallyapplied. Alternatively, they can be formed of wire wrapped into acylindrical shape or sheets of material formed into a cylindrical shape.

[0004] Stents are devices which are usually implanted within bodilyconduits including the vascular system to reinforce collapsing,partially occluded, weakened, or abnormally dilated sections of theblood vessel. Stents also have been successfully implanted in otherareas, e.g., the urinary tract or the bile duct to reinforce such bodilyconduits.

[0005] U.S. Pat. No. 4,994,071 (MacGregor) discloses an expandable,bifurcating stent having a main cylindrical lattice formed frominterconnected flexible wire. Two additional cylindrical lattices,having smaller diameters than the main lattice, are similarlyconstructed. The main lattice includes a flexible wire interconnectingthe main lattice to one of the additional lattices. A second flexiblewire interconnects the main lattice to the other additional lattice. Theflexible wires form backbones that extend axially along the length ofthe main lattice and along each of the additional lattices. Onedisadvantage of this bifurcating stent is the complex nature of theinterconnection of the flexible wires forming the backbones with theloop structure of each lattice.

SUMMARY OF THE INVENTION

[0006] The present invention solves these and other disadvantages of theprior art by providing bifurcated stents and methods of fabricating anddeploying bifurcated stents having a stem portion and two leg portions.

[0007] In a first embodiment of the invention, a bifurcated stent ismade by providing three sheets patterned to a desired pattern, whereintwo sheets are substantially the same size and the third sheet is widerthan either of the first two sheets. Each of the sheets is formed intotubes by turning up the longitudinal edges and forming a joint bywelding. The larger sheet forms a tube that acts as the stem portion ofthe bifurcated stent and the other sheets form tubes which act as theleg portions of the bifurcated stent. The two leg portions are thenjoined to the stem portion to form the bifurcated stent.

[0008] In a second embodiment of the invention, the bifurcated stent isformed by preparing two stent sheets. For each sheet, the longitudinaledges of a portion of the sheet are turned up and secured to each otherto form one of the two leg portions of the bifurcated stent. Theremaining free edges of each of the two sheets are then joined to formthe stem portion of the stent.

[0009] In a third embodiment, the bifurcated stent comprises first andsecond tubular portions. The first portion has a proximal end whichforms the stem portion and a distal end which forms one of the legportions of the bifurcated stent. A branch aperture is disposed betweenthe proximal end and the distal end of the first portion. The secondportion is introduced into the longitudinal bore of the stem portion ofthe first portion and is advanced through the branch aperture so that itprotrudes beyond the branch aperture to form a second leg. When thesecond portion is expanded, the proximal end of the second portionengages the material defining the branch aperture so as to secure thesecond leg in the desired position.

[0010] It is an object of this invention to provide a method of making abifurcated stent, comprising the steps of: a) preparing a first sheethaving a first edge, a second edge, a third edge, and a fourth edge; b)preparing a second sheet having a first edge, a second edge, a thirdedge, and a fourth edge; c) preparing a third sheet having a first edge,a second edge, a third edge, and a fourth edge; d) attaching the secondedge to the third edge of the first sheet to form a tubular first legportion having a proximal end and a distal end; e) attaching the secondedge to the third edge of the second sheet to form a tubular second legportion having a proximal end and a distal end; f) attaching the secondedge to the third edge of the third sheet to form a tubular stem portionhaving a proximal end and a distal end; and g) attaching the proximalend of the first leg portion and the proximal end of the second legportion to the distal end of the stem portion.

[0011] It is another object of this invention to provide a method ofmaking a bifurcated stent, comprising the steps of a) preparing a firstsheet having a proximal end and a distal end; b) deforming the distalend of the first sheet to form a first leg and deforming the proximalend of the first sheet to form a first stem half; c) preparing a secondsheet having a proximal end and a distal end; d) deforming the distalend of the second sheet to form a second leg and deforming the proximalend of the second sheet to form a second stem half; and e) joining thefirst stem half to the second stem half to form a stem.

[0012] It is yet another object of this invention to provide a method ofmaking a bifurcated stent comprising the steps of a) preparing a firstexpandable tubular member having a proximal end and a distal end and alongitudinal bore therethrough, the first tubular member provided with abranch aperture disposed between said proximal end and the distal end,the branch aperture communicating with said longitudinal bore and theaperture sized and adapted to receive and secure a second expandabletubular member; b) delivering the first expandable tubular member to abifurcated vessel having a first lumen and a second lumen so that thefirst expandable member is disposed within the first lumen and thebranch aperture communicates with the second lumen; c) expanding thefirst expandable member in an amount sufficient to secure the firstexpandable member in the first lumen; d) preparing a second expandabletubular member having a proximal end and a distal end and havinglongitudinal bore therethrough; e) widening the branch aperture; f)delivering the second expandable tubular member into the branch apertureso that the distal end of the second expandable tubular member isdisposed within the second lumen and the proximal end of the secondexpandable tubular member is disposed within the longitudinal bore ofthe first longitudinal member; and g) expanding the second expandabletubular member in an amount sufficient to secure the second expandabletubular member within the second lumen and within said branch aperture.

[0013] It is still another object of this invention to provide a methodof making a bifurcated stent comprising the steps of:

[0014] a) preparing a sheet having a proximal end, a distal end, alongitudinal axis, and a circumferential axis, the sheet provided with:

[0015] a first side having a proximal portion having a proximal end anda distal end and a distal portion having a proximal end and a distalend;

[0016] a second side having a proximal end and a distal end, the secondside disposed between the proximal end of the sheet and the distal endof the sheet;

[0017] a third side having a proximal end and a distal end, the thirdside disposed between the distal end of the second side and the distalend of the sheet;

[0018] a fourth side disposed between the proximal end of the proximalportion of the first side and the proximal end of the second side;

[0019] a fifth side disposed between the distal end of the distalportion of the first side and the distal end of the third side, thefifth side having a length that is shorter than the length of the fourthside; and

[0020] a sixth side disposed between the second side and the third side;

[0021] b) attaching the second side to the proximal portion of the firstside and attaching the third side to the distal portion of the firstside to form a first expandable tubular member having a longitudinalbore defining a longitudinal axis, the fourth side defining a proximalstent aperture communicating with the longitudinal bore, the fifth sidedefining a distal stent aperture communicating with the longitudinalbore, and the sixth side and the proximal end of the third side and theproximal end of the distal portion of the first side defining a sidebranch aperture communicating with the longitudinal bore and sized andadapted to receive and secure a second expandable tubular member;

[0022] c) delivering the first expandable tubular member to a bifurcatedvessel having a first lumen and a second lumen so that the firstexpandable tubular member is disposed within the first lumen and thebranch aperture communicates with the second lumen;

[0023] d) expanding the first expandable tubular member in an amountsufficient to secure the first expandable tubular member in the firstlumen;

[0024] e) preparing a second expandable tubular member having a proximalend and a distal end and having longitudinal bore therethrough;

[0025] f) delivering the second expandable tubular member into thebranch aperture of the first tubular member so that the distal end ofthe second expandable tubular member is disposed within the second lumenand the proximal end of the second expandable tubular member is disposedwithin the longitudinal bore of the first tubular member; and

[0026] g) expanding the second expandable tubular member in an amountsufficient to secure the second expandable tubular member within thesecond lumen and within the branch aperture.

[0027] It is yet another object of this invention to provide abifurcated stent comprising:

[0028] a) a first tubular member having a proximal end and a distal endand a longitudinal bore therethrough defining a longitudinal axis, thefirst tubular member comprised of a sheet having a proximal end, adistal end, a longitudinal axis, and a circumferential axis, the sheetprovided with:

[0029] a first side having a proximal portion having a proximal end anda distal end and a distal portion having a proximal end and a distalend;

[0030] a second side having a proximal end and a distal end, the secondside disposed between the proximal end of the sheet and the distal endof the sheet;

[0031] a third side having a proximal end and a distal end, the thirdside disposed between the distal end of the second side and the distalend of the sheet;

[0032] a fourth side disposed between the proximal end of the proximalportion of the first side and the proximal end of the second side;

[0033] a fifth side disposed between the distal end of the distalportion of the first side and the distal end of the third side, thefifth side having a length that is shorter than the length of the fourthside; and

[0034] a sixth side disposed between the second side and the third side;

[0035] b) means for attaching the second side to the proximal portion ofthe first side and the third side to the distal portion of the firstside so that the fourth side defines a proximal stent aperturecommunicating with the longitudinal bore, the fifth side defines adistal stent aperture communicating with the longitudinal bore, and thesixth side and the proximal end of the third side and the proximal endof the distal portion of the first side define a side branch aperturecommunicating with the longitudinal bore and sized and adapted toreceive and secure a second tubular member; and

[0036] c) a second tubular member having a proximal end and a distal endand having longitudinal bore therethrough, the second tubular memberdisposed within the branch aperture so that the proximal end of thesecond tubular member is disposed within the longitudinal bore of thefirst tubular member.

[0037] It is a further object of this invention to provide a method ofmaking a bifurcated stent comprising the steps of:

[0038] a) cutting a proximal member from a first expandable tube havinga first cross-sectional diameter, the proximal member having a proximalend and a distal end and a longitudinal bore therethrough;

[0039] b) cutting a distal member from a second expandable tube having asecond cross-sectional diameter smaller than the first diameter of thefirst tube, the distal member having a proximal end and a distal end anda longitudinal bore therethrough;

[0040] c) attaching a portion of the distal end of the proximal memberto a portion of the proximal end of the distal member so that thelongitudinal bore of the proximal member is in fluid communication withthe longitudinal bore of the distal member to form a first expandabletubular member having a proximal end and a distal end and a longitudinalbore therethrough, the unattached portion of the distal end of theproximal member and the unattached portion of the proximal end of thedistal member defining a side branch aperture communicating with thelongitudinal bore of the first tubular member and sized and adapted toreceive and secure a second expandable tubular member;

[0041] c) delivering the first expandable tubular member to a bifurcatedvessel having a first lumen and a second lumen so that the firstexpandable tubular member is disposed within the first lumen and thebranch aperture communicates with the second lumen;

[0042] d) expanding the first expandable tubular member in an amountsufficient to secure the first expandable tubular member in the firstlumen;

[0043] e) preparing a second expandable tubular member having a proximalend and a distal end and having longitudinal bore therethrough;

[0044] f) delivering the second expandable tubular member into thebranch aperture of the first tubular member so that the distal end ofthe second expandable tubular member is disposed within the second lumenand the proximal end of the second expandable tubular member is disposedwithin the longitudinal bore of the first tubular member; and

[0045] g) expanding the second expandable tubular member in an amountsufficient to secure the second tubular member within the second lumenand within the branch aperture.

[0046] It is yet a further object of this invention to provide abifurcated stent comprising:

[0047] a) a first tubular member having a proximal end and a distal endand a longitudinal bore therethrough, the first tubular member comprisedof a proximal member and a distal member, the proximal member having afirst cross-sectional diameter, a proximal end and a distal end and alongitudinal bore therethrough, and the distal member having a secondcross-sectional diameter smaller than the first diameter, a proximal endand a distal end and a longitudinal bore therethrough;

[0048] b) means for attaching a portion of the distal end of theproximal member to a portion of the proximal end of the distal member sothat the longitudinal bore of the proximal member is in fluidcommunication with the longitudinal bore of the distal member to formthe first tubular member, the unattached portion of the distal end ofthe proximal member and the unattached portion of the proximal end ofthe distal member defining a side branch aperture communicating with thelongitudinal bore of the first tubular member and sized and adapted toreceive and secure a second expandable tubular member; and

[0049] c) a second tubular member having a proximal end and a distal endand having longitudinal bore therethrough, the second tubular memberdisposed and secured within the branch aperture so that the proximal endof the second tubular member is disposed within the longitudinal bore ofthe first tubular member.

BRIEF DESCRIPTION OF THE DRAWINGS

[0050]FIG. 1 shows a bifurcated stent manufactured in accordance withthe present invention;

[0051]FIG. 2 shows sheets used to form the legs and stem of the stentshown in FIG. 1;

[0052]FIG. 3 shows the sheets shown in FIG. 2 after they have beenrolled into a tubular shape;

[0053]FIG. 4 is a perspective view of the tubes shown in FIG. 3 prior toassembly;

[0054]FIG. 5 is an end view of the tubes shown in FIGS. 3 and 4 afterthey have been assembled to form a stent;

[0055]FIG. 6 is a top view of the assembled apparatus shown in FIG. 5;

[0056]FIG. 7 shows sheets used to form another embodiment of abifurcated stent manufactured in accordance with the invention;

[0057]FIG. 7B shows sheets used to form another embodiment of abifurcated stent manufactured in accordance with the invention;

[0058]FIG. 8 shows the sheets of FIG. 7 with demarcation points;

[0059]FIG. 9 shows the sheets of FIG. 8 after they have been rolled intoa tubular shape;

[0060]FIG. 9B shows the sheets of FIG. 7B after they have been rolledinto a tubular shape;

[0061]FIG. 10 shows the tubes of FIG.9 just prior to assembly;

[0062]FIG. 10B shows the tubes of FIG. 9B just prior to assembly;

[0063]FIG. 11 is a side view of the tubes shown in FIGS. 9 and 10 afterassembly;

[0064]FIG. 11B is a side view of the tubes shown in FIGS.9B and 10Bafter assembly;

[0065]FIG. 12 is an end view of the assembled apparatus shown in FIG.11;

[0066]FIG. 12B is an end view of the assembled apparatus shown in FIG.11B;

[0067]FIG. 12C shows an alternative embodiment of a pattern that may beused in place of the patterns shown in FIGS. 7 and 7B;

[0068]FIG. 13 shows a stem and first leg portion and a second legportion used to form another embodiment of a bifurcated stentmanufactured in accordance with this invention;

[0069]FIG. 14 shows guide wires disposed in the trunk lumen and branchlumen to be treated;

[0070]FIG. 15 shows the stem and first leg portion shown in FIG. 13disposed on catheters and guide wires prior to introduction into thelumen to be treated;

[0071]FIG. 16 shows the stem and first leg portion shown in FIG. 13after it has been delivered to the bifurcation to be treated and priorto its expansion;

[0072]FIG. 17 shows the second leg portion shown in FIG. 16 after it hasbeen expanded;

[0073]FIG. 18 shows expansion of the branch aperture;

[0074]FIG. 19 shows the unexpanded second leg portion disposed in thebranch aperture;

[0075]FIG. 20 shows the expansion of the second leg portion shown inFIG. 19; and

[0076]FIG. 21 shows the assembled bifurcated stent disposed in thebifurcated lumen to be treated;

[0077]FIG. 22 shows a sheet used to form a first expandable tubularmember;

[0078]FIG. 23 shows the sheet of FIG. 22 after it has been formed into afirst expandable tubular member;

[0079]FIG. 24 shows the first expandable tubular member of FIG. 23 withcatheters inserted into the longitudinal bore and the side branchaperture;

[0080]FIG. 25 shows the first expandable tubular member of FIG. 24 afterexpansion with an unexpanded second tubular member being introduced intothe side branch aperture;

[0081]FIG. 26 shows the first expandable tubular member of FIG. 24 afterexpansion with an unexpanded second tubular member disposed in the sidebranch aperture;

[0082]FIG. 27 shows the second tubular member of FIG. 26 after it hasbeen expanded;

[0083]FIG. 28 shows a side view of a proximal member and a distal memberused to make an alternative embodiment of the invention;

[0084]FIG. 29 shows the proximal and distal members of FIG. 28 afterthey have been connected to form a first expandable tubular member;

[0085]FIG. 30 is an end view of FIG. 29;

[0086]FIG. 30A is an end view of FIG. 29 showing an alternativeembodiment in which a portion of the proximal member and a portion ofthe distal member have been deformed prior to being attached;

[0087]FIG. 31 shows the first expandable tubular member of FIG. 29 witha second expandable tubular member disposed within the side branchaperture;

[0088]FIG. 32 shows a sheet used to form a stent in accordance with theinvention;

[0089]FIG. 33 shows another embodiment of a sheet used to form a stentin accordance with the invention;

[0090]FIG. 33A shows a stent manufactured utilizing the sheet of FIG.33; and

[0091]FIG. 34 shows a sheet used to form a stent in accordance with theinvention.

DETAILED DESCRIPTION

[0092] In the embodiment illustrated in FIG. 1, the bifurcation stent 5comprises a first leg 10, a second leg 15, and a stem 20. FIG. 2 shows afirst sheet 25 which is used to form first leg 10, a second sheet 30which is used to form second leg 15, and a third sheet 35 which is usedto form stem 20. The first sheet 25 and second sheet 30 aresubstantially flat and are sized to a predetermined length and width.For many applications, the first sheet 25 and second sheet 30 will havesubstantially the same dimensions so as to produce legs 10 and 15 thatare substantially the same size, however, the legs 10 and 15, and thesheets 25 and 30 used to produce them, may be of varying sizes asspecific applications dictate. The stents of this invention may be sizedso that when assembled they are their final size, however, in apreferred embodiment the stents are expandable and sized and adapted toassume their final dimensions upon expansion. The stent sheets 70 and 75may be patterned or etched with perforations forming a variety ofpatterns as specific applications dictate to achieve the expandablefeatures required as previously discussed. The third sheet 35 is sizedso that when it is rolled into a tube its internal cross-section can bemade to accommodate the cross-sectional external diameters of first leg10 and second leg 15. First sheet 25 has a first edge 26, a second edge27, a third edge 28, and a fourth edge 29. Second sheet 30 has a firstedge 31, a second edge 32, a third edge 33, and a fourth edge 34. Thirdsheet 35 has a first edge 36, a second edge 37, a third edge 38, and afourth edge 39. After the sheet metal has been cut to form sheets 25,30, and 35, it is deformed and rolled so as to cause two opposite edgesto meet and create a cylinder. In the example shown in FIGS. 2 and 3,edge 27 is joined to edge 29 via weld run 14 to form first leg 10. Edge32 is joined to edge 34 via weld run 19 to form second leg 15. Edge 37is joined to edge 39 via weld run 29 to form stem 20. The edges may bejoined in a wide variety of ways well known to those skilled in the artas suitable for this purpose, e.g., screwing, crimping, soldering,however, in a preferred embodiment welding is utilized. In an especiallypreferred embodiment, spot welding is utilized. As shown in FIG. 3,first leg 10 has a proximal end 11, a distal end 12, and defines alongitudinal bore 13. Second leg 15 has a proximal end 16, a distal end17, and defines a longitudinal bore 18. The stem 20 has a proximal end26, a distal end 27, and defines a longitudinal bore 28. FIG. 4 showsthe first leg 10, second leg 15, and stem 20 just prior to assembly. Toform the bifurcated stent 5, the proximal end 11 of first leg 10 and theproximal end 16 of second leg 15 are joined to the distal end 27 of thestem portion 20 so that the longitudinal bores 13, 18, and 28 are incommunication with each other. FIG. 5 is an end view and FIG. 6 is aside view of the assembled apparatus.

[0093]FIG. 11 shows a second embodiment of a bifurcation stentmanufactured in accordance with this invention. The stent 50 is providedwith a first leg 55 and a second leg 60 attached to a stem portion 65.The bifurcation stent 50 is formed from a first sheet 70 and a secondsheet 75 as shown in FIG. 7. The stent sheets 70 and 75 may be patternedor etched with perforations forming a variety of patterns as specificapplications dictate to achieve the expandable features required aspreviously discussed. The sheets 70 and 75 are substantially flat andhave a predetermined length and width. First sheet 70 has a first edge71, a second edge 72, a third edge 73 and a fourth edge 74. The secondsheet 75 has a first edge 76, a second edge 77, a third edge 78, and afourth edge 79. To form the legs of the stent a portion of edge 72 isrolled towards a portion of edge 74 and a portion of edge 77 is rolledtowards a portion of edge 79. Demarcation points 80, 81, 82, and 83 areselected on sheets 70 and 75 as shown in FIG. 8. These demarcationpoints 80, 81, 82, and 83 are selected to meet the requirement ofspecific applications and may be adjusted depending upon the lengthrequired for legs 55 and 60 and the length required for stem 65.Demarcation points 80 and 81 that are equidistant from edges 73 and 71and demarcation points 82 and 83 that are equidistant from edges 76 and78 will result in a stent in which the legs 55 and 60 have a length thatis substantially equal to stem portion 65. If the demarcation points areselected to be closer to edges 73 and 78 than to edges 71 and 76 thestem will have a length that is greater than the length of each of thelegs. If the demarcation points are selected to be closer to edges 71and 76 than to edges 73 and 78, each of the legs 60 and 65 will have alength that is greater than the length of the stem 65. In a preferredembodiment, however, the demarcation points 80, 81, 82, and 83, areselected so that proximal edges 72″, 74″, 77″, and 79″ are about ⅓ thelength of edges 72, 74, 77, and 79. As shown in FIG. 8, demarcationpoint 80 divides edge 72 at approximately its midpoint into a distaledge 72′, and a proximal edge 72″. Demarcation point 81 divides edge 74at approximately its midpoint into a distal edge 74′, and a proximaledge 74″. Demarcation point 82 divides edge 77 at approximately itsmidpoint into a distal edge 77′ and a proximal edge 77″ and demarcationpoint 83 divides edge 79 at approximately its midpoint into a distaledge 79′ and a proximal edge 79″.

[0094] To form the stent, edge 72′ is connected to edge 74′ via weld run90 to form first member 95 having a first leg portion 55 and a firststem half 65′ as shown in FIG. 9. Edge 77′ is connected to edge 79′ viaweld run 91 to form second member 100 having a second leg portion 60 anda second stem half 65″. As previously discussed, the edges may beconnected in a variety of ways well known to those skilled in the art.FIG. 10 shows the first member 95 and the second member 100 shown inFIG. 9 in alignment just prior to assembly. To produce the bifurcatedstent 50 shown in FIGS. 11 and 12, edge 72″ is connected to edge 79″ viaweld run 92 and edge 74″ is connected to edge 77″ via weld run 93 sothat first stem half 65′ and second stem half 65″ form stem 65. FIG. 12is a cross-sectional end view of the stent shown in FIG. 11.

[0095] In the embodiment shown in FIG. 7, sheets 70 and 75 are squaresor rectangles. The sheets 70 and 75 are not limited to thisconfiguration, however, as shown in FIG. 7B. FIG. 11B shows abifurcation stent manufactured using the sheets 270 and 275 shown inFIG. 7B. The stent 250 is provided with a first leg 255 and a second leg260 attached to a stem portion 265. The bifurcation stent 250 is formedfrom a first sheet 270 and a second sheet 275 as shown in FIG. 7B. Thestent sheets 270 and 275 may be sized and etched as previouslydiscussed. As shown in FIG. 7B, first sheet 270 has a first edge 271, asecond edge 272, a third edge 273, a fourth edge 274, a fifth edge 275,and a sixth edge 276, a seventh edge 146, and an eighth edge 147. Thesecond sheet 275 has a first edge 277, a second edge 278, a third edge279, a fourth edge 280, a fifth edge 281, a sixth edge 282, a seventhedge 148, and an eighth edge 149. As shown in FIG. 9B, edge 274 isconnected to edge 276 via weld run 290 to form first member 295 having afirst leg portion 255 and a first stem half 265′. Edge 280 is connectedto edge 282 via weld run 291 to form second member 300 having a secondleg portion 260 and a second stem half 265″. As previously discussed,the edges may be connected in a variety of ways well known to thoseskilled in the art. FIG. 10B shows the first member 295 and the secondmember 300 shown in FIG. 9B in alignment just prior to assembly. Toproduce the bifurcated stent 250 shown in FIGS. 11B and 12B, edge 272 isconnected to edge 149 via weld run 292 and edge 278 is connected to edge147 via weld run 293 so that first stem half 265′ and second stem half265″ form stem 265. FIG. 12B is a cross-sectional end view of the stentshown in FIG. 11B. FIG. 12C shows an alternative pattern that may beused in place of the patterns shown in FIGS. 7 and 7B.

[0096] A third embodiment of this invention comprises two portions whichare deployed serially in two steps and assembled within the patient toform a bifurcated stent. FIG. 13 shows stem and first leg portion 110provided with a longitudinal bore 131 and having a proximal end 115defining a stem portion 125 and a distal end 120 defining a first legportion 130. Second leg portion 140 is provided with a longitudinal bore132 and has a proximal end 145 and a distal end 150. Stem and first legportion 110 and second leg portion 140 may be sized and patterned oretched as previously discussed. A branch aperture 135 is disposedbetween the proximal end 115 and the distal end 120 of stem and firstleg portion 110. The branch aperture 135 is sized to receive second legportion 140 and is adapted to engage and secure the second leg portion140 when it has been expanded within the branch aperture 135. Second legportion 140 is sized and adapted to engage and be secured into branchaperture 135 upon expansion. FIGS. 14 to 21 show how the bifurcatedstent is assembled within a bifurcated lumen. As shown in FIGS. 14 to21, the area to be treated is a bifurcated lumen having a first or trunklumen 190 and a second or branch lumen 195. As shown in FIG. 14, a firstguide wire 155 is introduced into the trunk lumen 190 and a second guidewire 156 is introduced into the branch lumen 195. As shown in FIG. 15, aballoon expandable stem and first leg portion 110 is disposed on the tipof a first balloon catheter 170 so that the balloon 175 is disposedwithin longitudinal bore 131. A second balloon catheter 171 is thenintroduced into longitudinal bore 131 of stem and first leg portion 110and is advanced so that the balloon 176 is disposed within aperture 135.First catheter 170 is mounted on first guide wire 155 and secondcatheter 171 is mounted on second guide wire 156. As shown in FIG. 16,the unexpanded stem and first leg portion 110 is guided to the area tobe treated so that first leg portion 130 is disposed within trunk lumen190 and branch aperture 135 communicates with branch lumen 195. Guidewire 156 facilitates the orientation of the branch aperture 135 with thebranch lumen 195. The size of the conventional catheters and balloons isnot to scale and details well known to those skilled in the art havebeen omitted for clarity. Balloon 175 is inflated which causes the stemand first leg portion 110 to expand, as shown in FIG. 17, to secure itin the desired position. After expansion, the external wall of stem andfirst leg portion 110 would contact the interior walls of trunk lumen190, however, a gap has been intentionally left for clarity. The balloon175 on first catheter 170 is left inflated and the balloon 176 on secondcatheter 171 is then inflated to enlarge the branch aperture 135 asshown in FIG. 18. As the branch aperture 135 is enlarged a portion ofthe stent defining the branch aperture 135 is pushed outward to form abranch securing lip 180.

[0097] Balloons 175 and 176 are deflated, second catheter 171 iswithdrawn, and second guide wire 156 is left in place in the branchlumen 195. Second leg portion 140 is then applied to second catheter 171so that balloon 176 is disposed in longitudinal bore 132 and secondcatheter 171 is then applied to second guide wire 156. Second legportion 140 is then guided to, and introduced into, the longitudinalbore 131 of the stem and first leg portion 110 and is advanced andpassed through branch aperture 135 so that the distal end 150 of thesecond leg portion 140 protrudes into the branch lumen 195 and theproximal end 145 communicates with longitudinal bore 131, as shown inFIG. 19. The balloon 176 on second catheter 171 is partially inflatedand the balloon 175 on first catheter 170 is then partially inflated toa pressure substantially equal to the pressure in balloon 176. Bothballoons 175 and 176 are then simultaneously inflated to substantiallyequal pressures. As shown in FIG. 20, inflation of the balloon 176 onsecond catheter 171 causes second leg member 140 to expand so that itsexternal walls engage and are secured to the area surrounding aperture135. Inflation of the balloon 175 on the first catheter 170 preventsstem and first leg portion 110 from collapsing when balloon 176 isinflated. After expansion, the external walls of second leg 140 wouldcontact the inner wall of lumen 195, however, a gap has beenintentionally left for clarity. The balloons 175 and 176 are deflated,catheters 170 and 171 and guide wires 155 and 156 are withdrawn, and theassembled bifurcated stent 160 is left in place as shown in FIG. 21.

[0098] FIGS. 22 to 31 show an especially preferred method of makingbifurcated stent in accordance with the invention. FIG. 22 shows a sheet300 used to form a first expandable tubular member 301. The sheet 300has a longitudinal axis 302, a circumferential axis 303, a proximal end304, a distal end 305, a first side 306, a second side 307, a third side308, a fourth side 309, a fifth side 310, and a sixth side 311. Thesheet 300 may be provided with a variety of patterns, however, in apreferred embodiment the sheet 300 is provided with a plurality ofexpandable cells 312 adapted to be substantially flexible prior toexpansion of the first tubular member 301 and substantially rigid afterexpansion of the first tubular member 301. In an especially preferredembodiment the flexible cells 312 of the sheet 300 are substantiallyuniform as shown in FIG. 22.

[0099] The first side 306 of the sheet 300 has a proximal portion 313having a proximal end 314 and a distal end 315. The first side 306 alsohas a distal portion 316 having a proximal end 317 and a distal end 318.

[0100] The second side 307 of the sheet 300 has a proximal end 319 and adistal end 320 and is disposed between the proximal end 304 of the sheet300 and the distal end 305 of the sheet 300.

[0101] The third side 308 of the sheet 300 has a proximal end 321 and adistal end 322 and is disposed between the distal end 320 of the secondside 307 and the distal end 305 of the sheet 300.

[0102] The fourth side 309 of the sheet 300 is disposed between theproximal end 314 of the proximal portion 313 of the first side 306 andthe proximal end 319 of the second side 307.

[0103] The fifth side 310 of the sheet 300 is disposed between thedistal end 318 of the distal portion 316 of the first side 306 and thedistal end 322 of the third side 308 and is provided with a length L1that is shorter than the length L2 of the fourth side 309. In apreferred embodiment, the length L1 of the fifth side 310 and the lengthL2 of the fourth side 309 are in a ratio of 10 about 5:7, i.e., thefifth side 310 has a length L1 that is about 70% of the length L2 of thefourth side 309. In an especially preferred embodiment the sheet 300 isetched with a plurality of substantially uniform cells 312 as previouslydiscussed and the number of cells disposed along the circumferentialaxis 303 of the fifth side 310 and the number of cells disposed alongthe circumferential axis 303 of the fourth side 309 are in a ratio ofabout 5:7.

[0104] A sixth side 311 is disposed between the second side 307 and thethird side 308. In an especially preferred embodiment, the first side306, second side 307, and third side 308 are substantially parallel toeach other and the fourth side 309, fifth side 310, and sixth side 311are substantially parallel to each other and the first side 306, secondside 307, and third side 308 are substantially perpendicular to thefourth side 309, fifth side 310, and sixth side 311.

[0105] To make the first expandable tubular member 301, the second side307 of the sheet 300 is attached via attaching means to the proximalportion 313 of the first side 306 of the sheet 300 and the third side308 of the sheet 300 is attached via attaching means to the distalportion 316 of the first side 306 of the sheet 300 to form a firstexpandable tubular member 301 having a longitudinal bore 323 defining alongitudinal axis 324 as shown in FIG. 23. The attaching step may becarried out utilizing a variety of attaching means well known to thoseskilled in the art as suitable for this purpose, however, in a preferredembodiment the attaching step is carried out utilizing screwing,crimping, soldering, welding, or spot welding. In the embodiment shownin FIG. 23 spot welding 325 has been utilized. After the sides have beenattached as discussed above, the fourth side 309 defines a proximaltubular member aperture or stent aperture 326 communicating with thelongitudinal bore 323, and the fifth side 310 defines a distal tubularmember aperture or stent aperture 327 communicating with thelongitudinal bore 323 as shown in FIGS. 23 and 26. The sixth side 311and the proximal end 321 of the third side 308 and the proximal end 317of the distal portion 316 of the first side 306 define a side branchaperture 328 (as shown in FIGS. 23-26) sized and adapted to receive andsecure a second expandable tubular member 329 (shown in FIGS. 26-27).The branch aperture 328 has a diameter D1 that is larger than thediameter D2 of the unexpanded stent, i.e., the branch aperture 328 islarger than the proximal and distal apertures 326 and 327 of the firsttubular member 301 both before and after the tubular member 301 isexpanded.

[0106] The first expandable tubular member 301 is then delivered tobifurcated vessel having a first lumen and a second lumen so that thefirst expandable tubular member is disposed within the first lumen andthe branch aperture communicates with the second lumen. In a preferredembodiment, delivery is via a balloon catheter as previously discussed.After it has been positioned, the first expandable tubular member isexpanded in an amount sufficient to secure the first expandable tubularmember in the first lumen.

[0107] A second expandable tubular member 329 is then prepared having aproximal end 330 and a distal end 331 and having longitudinal bore 332therethrough. The second expandable tubular member 329 (shown in FIGS.25, 26, and 27) may be patterned in the same way as the sheet 300 aspreviously discussed. In a preferred embodiment the cells 312 of thesheet 300 used to make the first expandable tubular member 301 and thecells 312′ of the second expandable tubular member 329 are substantiallyuniform.

[0108] The second expandable tubular member 329 is delivered into thelongitudinal bore 323 of the first tubular member 301, as shown in FIG.25, and is advanced into and beyond the branch aperture 328, as shown inFIG. 26, so that the distal end 331 of the second expandable tubularmember 329 is disposed within the second lumen and the proximal end 330of the second expandable tubular member 329 is disposed within thelongitudinal bore 323 of the first tubular member 301. The secondexpandable tubular member 329 is then expanded in an amount sufficientto secure the second expandable tubular member 329 within the secondlumen and within the branch aperture 328 of the first tubular member 301shown in FIG. 27.

[0109] Among the advantages that this embodiment provides is that thisstent provides a large branch aperture that facilitates the introductionof the second tubular member into the side branch or second lumen. Inaddition, this stent is especially suitable for the performance ofserial bifurcation stenting and also for stenting around a side branchbefore it is occluded.

[0110] FIGS. 28 to 31 shown an alternative embodiment and alternativemethod of making the first tubular member shown in FIGS. 23-27. In thisembodiment the first tubular member 400 (shown in FIG. 29) is comprisedof a proximal member 401 having a proximal end 402 and a distal end 403and a distal member 404 having a proximal end 405 and a distal end 406as shown in FIG. 28. The proximal member 401 has a longitudinal bore 415and is cut from a first tube 407 having first cross-sectional diameterD1. The distal member 404 has a longitudinal bore 416 and is cut from asecond tube 408 having a second cross-sectional diameter D2. D2 issmaller than D1. The tubes 401 and 404 may be etched or patterned aspreviously discussed before the proximal member 401 and distal member404 are cut from the tubes 407 and 408. Alternatively, the proximal anddistal members 401 and 404 may be etched or patterned after the proximaland distal members 401 and 404 have been cut from the tubes 407 and 408.To make the first tubular member 400, a portion of the distal end 403 ofthe proximal member 401 is attached via attaching means 417 to a portionof the proximal end 405 of the distal member 404 to form a first tubularmember 400 having a proximal end 409 and a distal end 410 and alongitudinal bore therethrough 411 as shown in FIG. 29. The members 401and 404 may be attached utilizing a variety of attaching means 417 aspreviously discussed, however, in a preferred embodiment the attachingmeans utilized is welding. In an especially preferred embodiment spotwelding is utilized. Because D2 is less than D1 the unattached portionof the distal end 403 of the proximal portion 401 and the unattachedportion of the proximal end 405 of the distal portion 404 define abranch aperture 412 as shown in FIG. 29 and FIG. 30 (which is an endview of FIG. 29). In some applications it may be desirable to have agreater portion of the distal end 403 of the proximal member 401 and theproximal end 405 of the distal member 404 contact each other before theyare attached in order to increase the strength of the first tubularmember 400. This may be accomplished by, e.g., by distorting, aligning,and contacting a greater surface area of the distal end 403 of theproximal member 401 and a greater surface area of the proximal end 405of the distal member 404 prior to attaching the distal end 403 to theproximal end 405. FIG. 30A is an end view of this embodiment and showsthat a greater surface area of the distal end 403 and the proximal end405 are attached when compared to the embodiment shown in FIG. 30. FIG.30A also shows that in this embodiment the branch aperture 412′ islarger than the branch aperture 412 shown in FIG. 30. A second tubularmember 413 may then be introduced into the branch aperture 412 and 412′and as previously discussed is expanded and secured so that a portion ofthe second tubular member 413 communicates with longitudinal bore 411 toform a bifurcated stent 414 (shown in FIG. 31).

[0111]FIG. 32 shows a simplified version of the “L” shaped sheet shownin FIG. 22. The sheet 500 of FIG. 32 may be described as a sheet havinga longitudinal axis 501 and a first portion 502 and a second portion503. The first portion 502 has a proximal end 504 and a distal end 505and a first lateral side 506 and a second lateral side 507. The lateralsides 506 and 507 of the first portion 502 are substantially parallel tothe longitudinal axis 501 and are disposed apart from each other a firstdistance d1 508. The second portion 503 has a proximal end 509 and adistal end 510 and a first lateral side 511 and a second lateral side512. The lateral sides 511 and 512 of the second portion 503 aresubstantially parallel to the longitudinal axis 501 and are disposedapart from each other a second distance d2 513 that is less than thefirst distance d1 508. The proximal end 509 of the second portion 503communicates with the distal end 505 of the first portion 502.

[0112] Making a stent utilizing the sheet of FIG. 32 comprises the stepsof: connecting the first lateral side 506 of the first portion 502 tothe second lateral side 507 of the first portion 502 and connecting thefirst lateral side 511 of the second portion 503 to the second lateralside 512 of the second portion 503 to form a first tubular member 301having a longitudinal bore 323 therethrough as shown in FIG. 23. Aportion of the distal end 505 of the first portion 502 and a portion ofthe proximal end 509 of the second portion 503 define a side branchaperture 328 as shown in FIG. 23. If it is desired to make a bifurcatedstent, a second tubular member 329 having a proximal end 330 and adistal end 331 and a longitudinal bore 332 therethrough may be disposedand secured within the branch aperture 328 of the first tubular member301 so that the longitudinal bore 332 of the second tubular member 329is in fluid communication with the longitudinal bore 323 of the firsttubular member 301.

[0113] a) FIG. 33 shows another embodiment of a sheet 514 used to make astent in accordance with Applicant's invention. FIG. 33 shows a sheet514 having a longitudinal axis 515 and a first portion 516 and a secondportion 517. The first portion 516 has a proximal end 518 and a distalend 519 and a first lateral side 520 and a second lateral side 521. Thelateral sides 520 and 521 of the first portion 516 are substantiallyparallel to the longitudinal axis 515 and are disposed apart from eachother a first distance d1 522. The second portion 517 has a proximal end523 and a distal end 524 and a first lateral side 525 and a secondlateral side 526. The lateral sides 525 and 526 of the second portion517 are substantially parallel to the longitudinal axis 515 and aredisposed apart from each other a second distance d2 527 that is lessthan the first distance d1 522. The proximal end 523 of the secondportion 517 communicates with the distal end 519 of the first portion516. Making a stent utilizing the sheet of FIG. 33 comprises the stepsof connecting the first lateral side 520 of the first portion 516 to thesecond lateral side 521 of the first portion 516 and connecting thefirst lateral side 525 of the second portion 517 to the second lateralside 526 of the second portion 517 to form a first tubular member 539having a longitudinal bore 528 therethrough as shown in FIG. 33A. Aportion of the distal end 519 of the first portion 516 and a portion ofthe proximal end 523 of the second portion 517 define a side branchaperture 529. If it is desired to make a bifurcated stent, a secondtubular member having a longitudinal bore may be disposed and securedwithin the branch aperture of the first tubular member so that thelongitudinal bore of the second tubular member is in fluid communicationwith the longitudinal bore of the first tubular member as previouslydiscussed.

[0114] b) The sheet of FIG. 33 may also be described as a sheet 530having a first side 531, a second side 532 , a third side 533, a fourthside 534, a fifth side 535, a sixth side 536, a seventh side 537, and aneighth side 538 as shown in FIG. 34. Making a stent 539 utilizing thesheet shown in FIG. 34 comprises the steps of connecting the second side532 to the eighth side 538 and connecting the fourth side 534 to thesixth side 536 to form a stent 539 having a longitudinal bore 528therethrough and wherein the third side 533 and the seventh side 537define a branch aperture 529 disposed between the first side 531 and thefifth side 535 as shown in FIG. 33A. If it is desired to make abifurcated stent, a second tubular member having a longitudinal bore isdisposed and secured within the branch aperture of the first tubularmember so that the longitudinal bore of the second tubular member is influid communication with the longitudinal bore of the first tubularmember as previously discussed.

[0115] c) An especially preferred method of making a bifurcated stentcomprises the steps of preparing a first expandable tubular memberhaving a proximal end and a distal end and a longitudinal boretherethrough. The first tubular member is provided with a branchaperture disposed between the proximal end and the distal end. Thebranch aperture communicates with the longitudinal bore of the firstexpandable tubular member and the aperture is sized and adapted toreceive and secure a second expandable tubular member. The firstexpandable tubular member is delivered to a bifurcated vessel having afirst lumen and a second lumen so that the first expandable tubularmember is disposed within the first lumen and the branch aperturecommunicates with the second lumen. The branch aperture is widened in anamount sufficient to further align the branch aperture with the secondlumen. As specific applications dictate, the portion of the firstexpandable tubular member defining the branch aperture may be adapted toform a branch securing lip when the branch aperture is expanded asufficient amount. The first expandable tubular member is then expandedan amount sufficient to secure the first expandable tubular member inthe first lumen. A second expandable tubular member is prepared having aproximal end and a distal end having longitudinal bore therethrough. Thesecond expandable tubular member is delivered into the branch apertureso that the distal end of the second expandable tubular member isdisposed within the second lumen and the proximal end of the secondexpandable tubular member is disposed within the branch aperture of thefirst tubular member and so that the longitudinal bore of the secondexpandable tubular member is in fluid communication with thelongitudinal bore of the first longitudinal tubular member. The secondexpandable tubular member is then expanded in an amount sufficient tosecure the second expandable tubular member within the second lumen andwithin the branch aperture of the first expandable tubular member.

[0116] Still another especially preferred method of making a bifurcatedstent comprises the steps of delivering a first guide wire into thefirst lumen of a bifurcated vessel having a first lumen and a secondlumen and delivering a second guide wire into the second lumen of thebifurcated vessel. A first expandable tubular member is prepared havinga proximal end and a distal end and a longitudinal bore therethrough.The first expandable tubular member is provided with a branch aperturedisposed between the proximal end and the distal end. The branchaperture communicates with the longitudinal bore and the branch apertureis sized and adapted to receive and secure a second expandable tubularmember. The first expandable tubular member is mounted on a firstballoon catheter and the first balloon catheter is mounted on the firstguide wire. The first expandable tubular member is delivered to thefirst lumen of the bifurcated vessel so that the first expandabletubular member is disposed within the first lumen and the branchaperture communicates with the second lumen. A second balloon catheteris mounted on the second guide wire and the balloon portion of thesecond balloon catheter is delivered into the side-branch aperture. Thesecond balloon catheter is inflated to widen the branch aperture in anamount sufficient to form a branch securing lip and to further align thebranch aperture with the second lumen. The first balloon catheter isthen inflated to expand the first expandable member in an amountsufficient to secure the first expandable member in the first lumen. Thefirst and second balloon catheters are deflated and the second ballooncatheter is removed. A second expandable tubular member is preparedhaving a proximal end and a distal end having longitudinal boretherethrough. The second expandable tubular member is mounted on thesecond balloon catheter. The second expandable tubular member, mountedon the second balloon catheter, is delivered into the branch aperture sothat the distal end of the second expandable tubular member is disposedwithin the second lumen and the proximal end of the second expandabletubular member is disposed within the branch aperture of the firsttubular member and so that the longitudinal bore of the secondexpandable tubular member is in fluid communication with thelongitudinal bore of the first longitudinal member. The first ballooncatheter is inflated. The second balloon catheter is inflated to expandthe second expandable tubular member in an amount sufficient to securethe second expandable tubular member within the second lumen and withinthe branch aperture. As specific applications dictate, the portion ofthe first tubular stent defining the side branch aperture may be adaptedto form a branch securing lip when the branch aperture is expanded asufficient amount. In one embodiment, the first balloon catheter isinflated before the second balloon catheter is inflated and the firstballoon catheter is left inflated until the second expandable tubularmember is secured within the branch aperture by the second ballooncatheter. In another embodiment, the first balloon catheter and thesecond balloon catheter are inflated simultaneously.

What is claimed is:
 1. A method of making a stent comprising the steps of: a) preparing a sheet having a first side, a second side, a third side, a fourth side, a fifth side, a sixth side, a seventh side, and an eighth side, and b) connecting the second side to the eighth side and connecting the fourth side to the sixth side so that the third side and the seventh side define a branch aperture disposed between the first side and the fifth side.
 2. The method of claim 1, further comprising the step of: c) disposing and securing a second tubular member having a longitudinal bore within the branch aperture of the first tubular member, the longitudinal bore of the second tubular member in fluid communication with the longitudinal bore of the first tubular member.
 3. A method of making a stent comprising the steps of: a) preparing a sheet having a longitudinal axis and a first portion and a second portion; the first portion having a proximal end and a distal end and a first lateral side and a second lateral side, the lateral sides of the first portion substantially parallel to the longitudinal axis and disposed apart from each another a first distance; the second portion having a proximal end and a distal end and a first lateral side and a second lateral side, the lateral sides of the second portion substantially parallel to the longitudinal axis and disposed apart from each other a second distance that is less than the first distance, the proximal end of the second portion communicating with the distal end of the first portion; b) connecting the first lateral side of the first portion to the second lateral side of the first portion and connecting the first lateral side of the second portion to the second lateral side of the second portion to form a first tubular member having a longitudinal bore therethrough, a portion of the distal end of the first portion and a portion of the proximal end of the second portion defining a side branch aperture.
 4. The method of claim 3, further comprising the step of: c) disposing and securing a second tubular member having a longitudinal bore within the branch aperture of the first tubular member, the longitudinal bore of the second tubular member in fluid communication with the longitudinal bore of the first tubular member.
 5. A method of making a bifurcated stent comprising the steps of: a) preparing a first expandable tubular member having a proximal end and a distal end and a longitudinal bore therethrough, the first tubular member provided with a branch aperture disposed between the proximal end and the distal end, the branch aperture communicating with the longitudinal bore and the aperture sized and adapted to receive and secure a second expandable tubular member; b) delivering the first expandable tubular member to a bifurcated vessel having a first lumen and a second lumen so that the first expandable member is disposed within the first lumen and the branch aperture communicates with the second lumen; c) widening the branch aperture in an amount sufficient to further align the branch aperture with the second lumen; d) expanding the first expandable member in an amount sufficient to secure the first expandable member in the first lumen; e) preparing a second expandable tubular member having a proximal end and a distal end having longitudinal bore therethrough; f) delivering the second expandable tubular member into the branch aperture so that the distal end of the second expandable tubular member is disposed within the second lumen and the proximal end of the second expandable tubular member is disposed within the branch aperture of the first tubular member, the longitudinal bore of the second expandable tubular member in fluid communication with the longitudinal bore of the first longitudinal member; and g) expanding the second expandable tubular member in an amount sufficient to secure the second expandable tubular member within the second lumen and within the branch aperture.
 6. The method of claim 5, wherein during step c) the branch aperture is widened in an amount sufficient to form a branch securing lip.
 7. The method of claim 5, wherein during step g) the second expandable tubular member is widened in an amount sufficient to form a branch securing lip.
 8. A method of making a bifurcated stent comprising the steps of: a) delivering a first guide wire into the first lumen of a bifurcated vessel having a first lumen and a second lumen; b) delivering a second guide wire into the second lumen of the bifurcated vessel; c) preparing a first expandable tubular member having a proximal end and a distal end and a longitudinal bore therethrough, the first tubular member provided with a branch aperture disposed between the proximal end and the distal end, the branch aperture communicating with the longitudinal bore and the aperture sized and adapted to receive and secure a second expandable tubular member; d) mounting the first expandable tubular member on a first balloon catheter, e) mounting the first expandable tubular member on the first guide wire, f) delivering the first expandable tubular member to the first lumen of the bifurcated vessel so that the first expandable member is disposed within the first lumen and the branch aperture communicates with the second lumen; g) mounting a second balloon catheter on the second guide wire; h) delivering the balloon portion of the second balloon catheter into the side-branch aperture; i) inflating the second balloon catheter to widen the branch aperture in an amount sufficient to further align the branch aperture with the second lumen; j) inflating the first balloon catheter to expand the first expandable member in an amount sufficient to secure the first expandable member in the first lumen; k) deflating the first and the second balloon catheters; l) removing the second balloon catheter; m) preparing a second expandable tubular member having a proximal end and a distal end having longitudinal bore therethrough; n) mounting the second expandable tubular member on the second balloon catheter; o) delivering the second expandable tubular member into the branch aperture so that the distal end of the second expandable tubular member is disposed within the second lumen and the proximal end of the second expandable tubular member is disposed within the branch aperture of the first tubular member, the longitudinal bore of the second expandable tubular member in fluid communication with the longitudinal bore of the first longitudinal member; p) inflating the first balloon catheter; q) inflating the second balloon catheter to expand the second expandable tubular member in an amount sufficient to secure the second expandable tubular member within the second lumen and within the branch aperture.
 9. The method of claim 8, wherein, during step i) the branch aperture is widened in an amount sufficient to form a branch securing lip.
 10. The method of claim 8, wherein during step q) the second expandable tubular member is widened in an amount sufficient to form a branch securing lip.
 11. The method of claim 8, wherein the first balloon catheter is inflated before the second balloon catheter is inflated and the first balloon catheter is left inflated until the second expandable tubular member is secured within the branch aperture by the second balloon catheter.
 12. The method of claim 8, wherein steps p) and q) are carried out simultaneously. 